BR112016026639B1 - FLUID PULSE GENERATOR VALVE, FLUID PULSE GENERATOR AND FLUID PULSE GENERATING METHOD IN A FLUID COLUMN - Google Patents

Abstract

FLUID PULSE GENERATOR VALVE, FLUID PULSE GENERATOR AND METHOD OF GENERATING FLUID PULSES IN A FLUID COLUMN Methods and apparatus are disclosed for generating fluid pulses in a fluid column, such as within a fluid column. pit. An exemplary fluid pulse generator described has a valve member comprising a piston that is linearly movable within a piston chamber to control flow by selectively occluding a fluid passage. The fluid passage may extend around at least a portion of the piston chamber and intersect at an angle to the axis of motion of the valve member. The piston is linearly movable, such as from a minimum flow or closed position to a maximum flow position, and optionally to any one of a number or range of positions therebetween. The position of the valve member can be varied to generate fluid pulses of a selected pattern of duration, amplitude, and so on, to generate a signal within the fluid column detectable at a location remote from the pulse generator. fluid.

Description

FUNDAMENTALS

[0001] This disclosure generally refers to methods and apparatus for generating pulses from a fluid column, such as may be used for telemetry between a surface location and downhole instrumentation within an underground well.

[0002] Drilling fluid circulated down a drill string to lubricate the bit and remove cuttings is widely referred to as drilling "sludge". The use of pulses in a column of drilling fluid is commonly referred to as "mud pulse telemetry". Numerous fluid pulsation systems have been used to generate such pulses in the fluid column. Such systems include various forms of valve mechanisms to produce fluid pulses. A "trigger" valve, for example, may have a valve member that linearly reciprocates to open and close a fluid passage. A rotary valve, by comparison, may have a rotor that rotates to selectively control the flow of a fluid passage. The rotary valve may, either reciprocally rotate, relatively open and close a fluid passage to generate pulses, or continuously, whereby the rotor speed may be varied to facilitate pulses at a selected frequency momentarily to execute a desired communication protocol. Each of these systems has several features and characteristics.

BRIEF DESCRIPTION OF THE FIGURES

[0003] Figure 1 shows a schematic representation of an example tool string within an exploration well, the tool string including a mud pulse generator in accordance with the present disclosure.

[0004] Figures 2A-C represent examples of structures for use in generating fluid pulses; wherein Figure 2A schematically represents an illustrative example valve assembly in an "open" position and Figure 2B schematically represents the example valve assembly of Figure 2A in a "closed" position; while Figure 2C depicts an exemplary embodiment of a slurry pulse generator, including an example valve assembly, shown partially in vertical section.

[0005] Figures 3A-B show the valve assembly of the example mud pulse generator of Figure 2C in more detail, represented in longitudinal section in Figure 3A and in lateral cross section in Figure 3B.

[0006] Figure 4 represents a vertical cross-section of an alternate embodiment of a mud pulse generator valve assembly.

[0007] Figure 5 represents a vertical cross-section of another alternative embodiment of a slurry pulse generator valve assembly.

[0008] Figure 6 represents a vertical cross-section of an alternative configuration for use with a mud pulse generator such as Figure 2C.

[0009] Figure 7 represents a vertical cross-section of another alternative configuration for use with a mud pulse generator such as Figure 2C.

[0010] Figure 8 represents a block diagram of an example electronics section suitable for use in the mud pulse generator of Figure 2C.

[0011] Figure 9 represents a flowchart of an example method for using a mud pulse generator valve assembly of any of the types described herein.

DETAILED DESCRIPTION

[0012] The present disclosure includes novel methods and apparatus for generating fluid pulse telemetry signals, wherein a linearly moving valve member, such as a piston, moves within a piston chamber defined at at least in part by a surface, to selectively obstruct fluid flow and thereby control the rate of fluid flow through openings in said surface. The surface opening(s) may represent or be defined by the respective intersection of one or more fluid flow passage(s) with the piston chamber. In some exemplary embodiments, the fluid flow passage will extend around a portion of the piston chamber to intersect a downstream portion of the piston chamber. In some exemplary embodiments, the piston moves along a linear axis and the fluid flow passage will intersect the piston chamber surface at an angle to said linear axis of motion.

[0013] The linear motion valve member may fully, or at least partially, obstruct flow to or from the fluid flow passage when in a first position (i.e. to close or at least reduce flow relative to a second position) and to allow and/or increase flow to or from the fluid flow passage when moved from the first position to the second position. This description is not intended to limit the linearly moving valve member to having two positions, not just the discrete positions. Instead, in at least some embodiments, the linearly moving valve member may be varied over a range of positions to selectively occlude the fluid passage and thus vary the fluid flow by an amount that varies with the position of the valve. linear motion valve member and corresponding obstruction of the fluid flow passage.

[0014] In some embodiments, the movable valve member will include a closing member configured to open or close flow through one or more fluid flow passages in a desired manner. In some embodiments, the valve closing member will generally open or close a fluid passage that is arranged radially with respect to the axis of linear motion of the valve member. In some embodiments, the piston chamber will have a region with surfaces that define a generally uniform bore of a selected distance, and the valve includes one or more fluid passages extending into the opening(s) in said surface and the closing member is linearly movable within the hole to open or close the flow of fluid through the openings.

[0015] The following detailed description describes exemplary embodiments of the associated methods and novel mud pulse generator with reference to the accompanying figures, which illustrate various details of examples that show how the disclosure can be put into practice. The discussion addresses several examples of novel methods, systems, and apparatus in connection with these drawings, and describes the embodiments depicted in sufficient detail to allow those skilled in the art to practice the disclosed subject matter. Many modalities in addition to the illustrative examples discussed in this document can be used to practice these techniques. Structural and operational changes, in addition to the alternatives specifically discussed herein, may be made without departing from the scope of the present disclosure.

[0016] In this description, references to "the embodiment" or "an embodiment", or to "the example" or "an example", in this description are not necessarily intended to refer to the same embodiment or example; however, neither are these two embodiments mutually exclusive, unless this is stated or as will become readily apparent to individuals of ordinary skill in the art who have the benefit of this disclosure. Accordingly, a variety of combinations and/or integrations of the modalities and examples described herein may be included, as well as additional modalities and examples, as defined within the scope of all claims based on this disclosure, as well as all legal equivalents of such claims.

[0017] A mud pulse generator as described here will be used to generate pulses from a column of fluid within a downhole as well as facilitate "mud pulse telemetry". This terminology embraces communication through pulses in a column of fluid of any type (or produced fluid) that may be in a well. An example of such use is for the mud pulse generator to be placed on a drill string together with MWD (or LWD) tools, for data communication from the MWD/LWD tools up and to the surface through the column of fluid flowing down through the drill bit to exit the drill bit. The pulses will be detected and decoded at the surface, thereby communicating data from tools or other sensors on the entire lower assembly, or elsewhere on the drill bit. The described example mud pulse generator relatively opens and closes the fluid passages to create pulses in the fluid column of a selected time pattern and which are detectable at the surface. In other contemplated systems, a mud pulse generator as described may be placed near the surface to provide downlink pulse communication to a downhole tool.

[0018] Referring now to Figure 1, the Figure schematically shows an example of the directional drilling system 100 configured to form exploration wells in a variety of possible trajectories, including those deviating from the vertical. Directional drilling system 100 includes an earth drilling rig 112 to which a drill assembly, indicated generally at 104, with a bottom hole assembly, indicated generally at 144 (hereinafter BHA) is connected, in accordance with that disclosure . The present specification is not limited to shore drilling equipment and example systems according to the present disclosure may also be employed in drilling systems associated with offshore platforms, semi-submersibles, drillships and any other drilling system suitable for the formation of an exploration well that extends through one or more downhole formations. Drilling rig 112 and associated surface control and processing system 140 may be located in close proximity to wellhead 110 on the Earth's surface. Drilling equipment 112 may also include a rotary table and rotary drive motor (not specifically shown) and other equipment associated with rotation or other movement of drillstring 104 within exploration well 116. Other components for drilling and/or management wellheads such as safety valves (not expressly shown) will also be provided near wellhead 110. A ring 118 is formed between the outside of the drillstring 104 and the forming surfaces defining exploration well 116.

[0019] One or more pumps will be provided to pump the drilling fluid, indicated generally at 128, from a fluid reservoir 126 to the upper end of the drilling chain 104 which extends from the wellhead 110. Return drilling fluid, formation cuttings and/or downhole debris from the downhole end 132 of exploration well 116 will return through ring 118 through various conduits and/or in other devices to fluid reservoir 126. Various types of tubes, tubing and/or other conduits can be used to form complete fluid paths.

[0020] BHA 106 at the lower end of drill string 104 terminates in a drill bit 134. Drill bit 134 includes one or more fluid flow passages with respective nozzles disposed therein. Various types of well fluids can be pumped from the reservoir 126 to the end of the drillstring 104 which extends from the wellhead 110. The well fluid(s) flow through a longitudinal hole (not expressly shown) into the drillstring 104 and exits the nozzles formed in the bit 134. During drilling operations the drilling fluid will mix with formation cuttings and other downhole debris near the bit 134. The drilling fluids will then flow upward through ring 118 to return formation cuttings and other downhole debris to the surface. Various types of screens, filters, and/or centrifuges (not expressly shown) will typically be provided to remove formation cuttings and other downhole debris prior to returning drilling fluid to reservoir 126.

[0021] Bottom hole assembly (BHA) 106 can include several components, for example, one or more measurement while drilling (MWD) or logging while drilling (DPM) tools 136, 148 that provide data logging and other information to be communicated from downhole exploration 116 to surface equipment 108. In this example column, the BHA 106 includes mud pulse generator 144 to provide mud pulse telemetry of that data and/or other information through the fluid column inside the drillstring to a surface receiver location, for example, in the vicinity of wellhead 110. Mud pulse generator 144 will be constructed in accordance with the exemplary device of Figure 2 and/or any of the following. other example modalities described herein. At the surface receiver location, pressure pulses in the fluid column will be detected and converted to electrical signals for communication with surface equipment and potentially from there to other locations.

[0022] The communicated log data and/or other information communicated to a receiver hole top may then be communicated to a data processing system 140. The data processing system 140 may include a variety of hardware, software and combinations thereof, including, for example, one or more programmable processors configured to execute instructions in and retrieve data from and store the data in a memory to perform one or more functions assigned to data processing system 140 herein . The processors used to perform the functions of the data processing system 140 may each include one or more processors, such as one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gates (FPGA), a programmable logic circuit and the like, either singly or in any suitable combination.

[0023] For some applications, the data processing system may have a printer, display and/or additional associated devices to facilitate control of record drilling and exploration operations. For many applications, the outputs of the data processing system will be communicated to the various components associated with the operational drilling rig 112 and can also be transmitted to various remote locations that monitor the performance of operations performed through the directional drilling system 100.

[0024] Referring now to Figure 2A, the figure schematically represents an example of valve mechanism 150 illustrated in simplified form, to represent the movement and function of the valve closing mechanism. Mechanism 150 includes a sub-port 152 within a housing 154. In that exemplary configuration, the sub-port 152 in combination with housing 154 defines a plurality of fluid flow passages that include channels 156. In many examples, the channels 156 are in fluid communication with a fluid-containing annular region (not shown in this figure) above the valve mechanism within housing 154, through which well fluids are pumped. The fluid flow passages further include radially extending passages 158 which each communicate with channels 156 and extend to intersect a central hole 162 through which fluid will flow. Central bore 162 is a downstream portion of a chamber, indicated generally at 174, which contains a longitudinally movable valve member, here in the form of a piston 164 configured to reciprocate movement in response to a drive mechanism 170. Each radially extending passage 158 terminates in an opening 160 in a surface 176 defining the center hole 162 of piston chamber 174. The fluid flow passages will be sized to allow the passage of expected particles that can be dispersed in a drilling fluid. , such as various forms of "flow loss materials" that can be introduced into a fluid to treat fluid loss in formations penetrated by the exploration well.

[0025] In the example shown, the drive mechanism 170 can be any one of a variety of mechanisms, such as hydraulic, electrical, mechanical mechanisms, etc., and thus is generically represented in the figure. As will be described here later, electrical mechanisms are believed to be suitable as drive mechanisms and example alternatives to electromagnetic drive mechanisms are discussed hereafter.

[0026] In this example, the piston 164 includes a radially enlarged closure member, indicated generally at 166. The closure member 166 includes a radially outward surface 168. The piston 164 is linearly movable between at least the first and the second positions along a longitudinal axis of movement 172 and may be movable with respect to one or more positions between the first and second positions or to a side of one of said first and second positions. In Figure 2A, the piston 164 is in a relatively retracted position, in which the valve assembly is "open", because the outer surface 168 of the closing member 166 is longitudinally above (or "bore top") the openings 160 and thus openings 160 are unobstructed to provide free flow of fluid from channels 156 through passages 158 and associated openings 160 in central bore 162 of piston chamber.

[0027] Referring now also to Figure 2B, the figure illustrates the piston 164 in a second longitudinal position, in which the piston 164 is relatively extended and the valve mechanism 150 is "closed" by virtue of the radially outward surface 168 of the closure member 166 being longitudinally adjacent openings 160 to relatively restrict, or block, the flow of fluid from passages 158 in central bore 162. For purposes of generating fluid pulses, complete blocking or "sealing" of openings 160 is not it is necessary. In that example, the closure member 166 has openings within the perimeter defined by the outer surface 168 to allow the closure member 166 to reciprocate through fluids with less resistance; and the surfaces of the closure member 166 can be configured to minimize such resistance. In this example, the piston 164 moves linearly with respect to the flow flowing radially inwardly at an angle to the axis of movement 172. Thus, in this example configuration, the valve mechanism 150 operates primarily in shear with respect to the flowing fluid and the movement of piston 164 does not have to overcome the weight of the column of fluid above the valve mechanism in either direction of reciprocating movement.

[0028] Referring now to Figure 2C, the figure illustrates an example of the mud pulse generator 200, represented partially in vertical section. Slurry pulse generator 200 will utilize a valve assembly that operates generally in accordance with the above schematic example (which may be implemented in a variety of configurations, including but not limited to example configurations as described herein). In this example, the mud pulse generator 200 includes a housing assembly 202, which, in this example, includes an outer housing 204 that has box connections and pin connections 206, 207, respectively, at the upper and lower ends, as well as a center insert 206 and a hole insert outlet 208 as will be further discussed hereinafter with reference to Figure 3A.

[0029] Mud pulse generator 200 includes three sets of primaries which will be discussed below: a power source for operating the device (in this example, a generator set, generally indicated at 210); an electronics section 226 and a valve assembly 230. Generator set 210 includes a generating section, indicated generally at 212, which will include a stator and rotor (not specifically illustrated) cooperatively configured to generate electrical current for use by the pulse generator of mud 200, in response to the rotation of the rotor relative to the stator. Generator set 212 also includes, in this example, an adjustable multifaceted flow gear 214, comprising a plurality of vanes configured to engage fluid flowing downwardly in annular space 216 around generator set 210 within outer housing 204, and prepares for coupling to generator 212. Flux gear 214 is operatively coupled to generator rotor 212 to cause it to rotate to generate electrical current. At an upper end, generator set 210 includes a tapered nose 222 for directing fluid flow to annular space 216, where fluid will surround first and second stage vanes, 228A, 228B, respectively. In some systems, the tapered nose 222, or other component in its place, may be configured to facilitate attachment to another tool, such as any one or more electrical, optical, hydraulic, pneumatic, and/or mechanical attachments ( as discussed herein with reference to Figure 6). In this example, a centralizer 224 is coupled between the flow gear 214 and the generator 212 to keep the generator set 210 centered within the outer shell 204, thereby defining a portion of a generator set 216 around the annular space 210 within the outer shell 204.

[0030] In this example, the mud pulse generator 200 includes an electronics section 226 beneath the generator set 210, and operatively coupled thereto. Again, a centralizer 232 is located between the generator set 210 and the electronics section 226. Due to the transmission of electrical current between the generator and the electronics section, an airtight seal 234 will be provided between the two sections. In the example shown, the seal is located within the centralizer 232, but may alternatively be located either on the generator set 210 or on the electronics section 226 or another intermediate component.

[0031] Electronics section 226 typically includes a sealed enclosure 236 to isolate the contained circuit and components from the outside environment. In this example, the electronics section 226 includes both an electrical storage mechanism for receiving electrical current produced by the generator set 210 and the control circuits for the mud pulse generator 200.

[0032] Referring now to Figure 8, that figure shows a block diagram representation of an example electronics section 226 suitable for use as a component of the mud pulse generator 200. As shown in this figure, the electronics section of 226 includes an electrical storage device 802, in this example coupled to receive an electrical current input 804 from the generator set 210. Electrical storage device 802 may be of any known type suitable for the requirements of the remainder of the pulse generator of mud 200, such as a battery or a capacitor. Electronics section 226 also includes a power controller 806 operatively coupled to electrical storage device 802. Power controller 806 is typically structured to perform a number of functions, including regulating voltage and/or current supplied to other components. This power regulation often includes various ways of filtering the electrical signal to remove noise or other anomalies. Although power controller 806 is described as being downstream of electrical storage device 802, many functions of the controller can be performed before the electrical signal from generator 212 is coupled to electrical storage device 802, and therefore the current at from generator 212 may be coupled to power controller 806, instead of electrical storage device 802. In such configurations, power controller 806 may also include appropriate storage/battery management functionality.

[0033] Electrical current will be transmitted from any power controller 806 or electrical storage device 802 to other electrical components in the system. In the example shown, these include a data signal processing/encoding module 808 providing functionality as described later herein with reference to Figure 6, to receive one or more data signals through one or more inputs, as indicated in 810, and to prepare such signal(s) for transmission through a series of mud pulses. Once a portion of a data stream is ready for transmission, the data stream will be transmitted to a valve controller 812 to provide appropriate control signals to the valve assembly 230.

[0034] In some example systems, one or more feedback signals are received at an input 814 and used to optimize the performance of the mud pulse generator 200, such as by adjusting the operation of the valve controller 812. Return can be from a variety of potential sources. For example, one or more sensors may be located relatively upstream in the tool chain containing mud pulse generator 200, where they may detect pulses generated or other conditions in the exploration well to provide adequate feedback. Such feedback signal can be analyzed within valve controller 812 to adjust valve operation. For example, if the analysis of the feedback signal was to indicate less than a threshold or desired pulse of identification or discrimination, valve controller 812 can be triggered to adjust valve operation, for example, controlling the valve either to reduce the transmission rate (and eventually extend the pulse duration) and/or to increase the pulse amplitude. In some situations, valve controller 812 may determine that a different transmission protocol would be more suitable for existing downhole conditions, and may transmit (as indicated at 818) to the data signal processing/encoding module 808 an instruction to make such a change.

[0035] Other sources of return signals are also contemplated. For example, feedback can be obtained from the pulse receiver in the vicinity of the wellhead, and transmitted along the hole by any suitable mechanism, such as a pulse fluid downlink, wire tube, or a flow channel. transmission including a portion which is a wireless transmission link. Furthermore, in addition to detecting fluid pulses, other types of sensors can be used, such as acoustic sensors to detect noise in exploration well sensors, vibration or other motion sensors (e.g. accelerometers) associated detection motion. with the toolkit, etc.

[0036] In order to provide the functionality described, electronics section 226 typically includes one or more processing resources, such as a programmable processor or controller, and where a programmable device is used, it may also include random access memory. (RAM), hardware and/or software control logic, other storage to contain data and/or operating instructions, read-only memory (ROM), and/or other types of non-volatile memory. For purposes of the present disclosure, all memory devices, whether volatile or non-volatile, and storage units are considered non-transient storage devices. In addition, the electronics section 226 comprises appropriate interface circuitry 820 for transmitting and receiving data from sensors located on the surface and/or downhole, and may include one or more transmission ports with external devices, as well as any additional input and output (I/O) device required.

[0037] In one example, electronics section 226 has programmed instructions stored in memory that, when executed, execute the described control operations. While the described electronic system functionality is described and represented as separate with reference to Figure 8, such description is for clarity of description, any or all of such functionality may be performed by a single processor or controller, if desired.

[0038] Referring again to Figure 2C, in the example shown, the electronics section 226 is coupled to the valve assembly 230 through the use of a connection block 238 between the two units. Again, an airtight seal 240 will be provided between the two units to isolate the electrical connections between the two components. Although in the illustrated example, generator set 210 and electronics section 226 are described as being located upstream of valve assembly 230, these components may instead be located along the bore of valve assembly 230. In other examples, The structure and functionality of the electronics section 226 can be provided by two or more separate assemblies within a mud pulse generator, an example of which is discussed herein with reference to Figure 7.

[0039] Referring now also to Figures 3A-B, Figure 3A depicts the valve assembly 230 in greater detail, and partially in longitudinal section, while Figure 3B depicts a lateral cross-section of the valve assembly 230 through the member 254. As can be seen in Figure 3A, in this region, housing assembly 202 includes not only outer housing 204, but a center insert 206 and an exit hole insert 208. Center insert 206 tightly surrounds the inner hole of the outer casing 204. In a relatively higher section, central insert 206 includes a plurality of ribs around its outer surface extending generally the inner diameter of the outer casing 204 to define passageways 242A, 242B in communication with the annular space 216 above. In a relatively low portion, central insert includes a plurality of generally radially extending passages 244A, 244B connecting passages 242A, 242B defined by said splines within outer shell 204. In this exemplary configuration, each passage 244A, 244B terminates in a respective opening, each indicated at 248, to a central hole 240 in central insert 206. Passages 244A, 244B will preferably extend at some angle relative to central hole 240. While this angle may be any desired, in many examples, the angle included between each passage 244A, 244b and a longitudinal axis through center hole 240 will be less than 90 degrees to minimize obstruction to fluid flow, and in many instances will be less than about 45 degrees, as in the example described .

[0040] Valve assembly 230 includes a valve member configured for linear reciprocating within the valve assembly 230, which is identified as piston 250. In the described example, piston 250 is constructed of at least two pieces, a drive member 252 and a lock member 254 coupled to the drive member 252 for movement together, such that reciprocating movement of the drive member 252 causes the lock member 254 to move between one or more positions relative to each other. in register with the apertures 248 to relatively close the fluid path into the central hole 240, and one or more positions relatively out of registration with the apertures 248 to relatively open the fluid path into the central hole 240. closure 254 can be of many possible configurations which will restrict fluid between openings 248 and central hole 240 when in a first position and allow such fluid transmission when in a second position. In the example described, the closure member includes an outer ring 270 supported by a plurality of spokes 272 relative to a central hub 274. Central hub 274 facilitates attachment of closure member 254 to drive member 252. While closure member 254 has been described as a separate structure from the drive component 252, in other examples both may be formed as a single component.

[0041] In the example described, fluid will flow into the central hole 240 from the passages 244A, 244B. However, configurations are possible that would allow the flow to be in the opposite direction, as if the described components were inverted in orientation. The described configuration is desirable, however, as it removes the piston 250 from the pressure exerted by the fluid column on the tooling, and allows the closing member to open and close the fluid passages when actuating essentially with respect to shear. for the flowing fluid. 250 piston being placed for movement outside the column of fluid allows for easier movement in both directions as the drive mechanism does not need to overcome the weight and force of the column of fluid when moving in either direction. Examples of this configuration offer a significant advantage over valves with a movable frame member that is exposed to the fluid column above (such as conventional poppet valves), which must overcome the weight and pressure of the column when moving in one of the two directions.

[0042] In the described example, the outer ring 270 of the closure member 254 has a circumferential periphery having a central section 276 that has a generally cylindrical profile, providing a "sealing" surface. Closing member 254 is sized such that center section 276 provides a relatively small tolerance in center hole 256 to substantially block fluid flow between openings 248 and center hole 240. It should be understood that complete closure (i.e., literal "sealing") of the fluid flow passages is not necessary for the generation of the fluid pulses. Indeed, in some examples, closure member 254 may be configured to leave "open" (i.e., unblocked) one or more openings 248 even when in a relatively "closed" position, so as to always allow for some degree of leakage. fluid; or some fluid flow may be allowed through the dimensions of the closure member 254 being selected to allow a desired clearance, even when in registration with the apertures (e.g., in a "closed" position). Thus, the "opening" and "closing" of the valve are not absolute numbers, but are relative to each other, which indicates that it allows and obstructs the flow of fluid to a desired degree of generating fluid pulses, while meeting the requirements of the downhole operations (such as fluid flow to the bit during drilling operations).

[0043] In this configuration example, closing member 254 is configured to block all openings 248 and therefore has a continuous outer periphery. Outer ring 270 includes tapered sections 278A, 278B on either side of center section 276 tapering in a radially inward direction, which minimizes resistance to fluid movement of closure member 254 in both directions. In addition, the conicals shown will help to release closure member 254 of any solids that could become trapped and thereby block or impede movement of the closure member. Enclosure member 254 will preferably be constructed of a relatively lightweight material that is capable of withstanding fluid and ambient pressures along the hole in which it is to be used. A suitable material for the closure member 254 is titanium, to minimize the mass of the closure member 254, thereby facilitating relatively rapid reciprocal movement or other movement within the central hole 240. Other suitable materials would be ceramic, stellite and/or carbon carbide. tungsten, each of which can offer particular advantages with respect to specific downhole conditions).

[0044] A driver section, indicated generally at 280, is configured to move the plunger 250 back and forth along the linear path. Actuator section 280 can be of many possible configurations, and can be operated for example either electrically or hydraulically. In the example shown, the trigger section 280 is electrically operated. The drive mechanism may be a solenoid or other appropriate mechanism, for example a voice coil selectively generating it from a magnetic field to interact with a magnetic field created by one or more permanent magnets to reciprocate the piston 250. type of drive mechanism, the coils can be more easily placed in a valve housing 256 which will remain stationary with respect to the center insert 206, thereby facilitating practical wiring considerations from the electronics section 226 to one or more coils 258A, 258B located in respective recesses 260A, 260B on the inner periphery of valve housing 256. Valve housing 256 will be formed of a non-magnetic material. The drive member 252 includes one or more cavities 262A, 262B that extend at least partially around the periphery of the drive member 252 with each cavity housing one or more respective permanent magnets, indicated generally at 264A, 264B.

[0045] The described drive mechanism, using coils that interact with the magnetic fields established by permanent magnets can be implemented in a way that offers specific advantages. For example, as can be seen from the conductor section 280, no physical coupling with drive member 252 is necessary to cause the desired motion; and movement will occur even with well fluids around the drive member 252 in the valve housing 256. As a result, no dynamic seal is required between the drive member 252 and the valve housing 256 (or similar structure). Such dynamic seals can, in some implementations, prevent movement of a moving member (here, drive member 252) and/or serve as a potential point of failure. While such a dynamic seal could be added to conductor section 280 if desired for some applications or configurations, in the embodiment shown, one is not required for the described operation of conductor section 280.

[0046] A number of specific configurations for coils and permanent magnets are provided. In some cases, multiple coils can be driven with opposite polarities of electrical current to generate reciprocal motion of piston 250. In other examples, however, each coil can be driven with a single polarity of electrical current, with the change in direction achieved. through the orientation of the magnetic fields of the permanent magnets and the relative positioning of the permanent magnets. In any type of system, multiple coils can be sequentially driven to achieve the desired movement of piston 250. In this example, valve housing 256 and coils 258 extend concentrically around drive member 252. While this configuration offers advantages , it should be understood that other mechanisms may be used where the electromagnetic coils or other structures are not concentric to the drive member 252, however, are placed relatively radially outward from the drive member 252.

[0047] In the illustrated embodiment of the valve assembly 230, the central hole 240 has a generally circular cross-section. However, other configurations can be used, such as an oval cross-section for the orifice, which can be used to prevent rotation of the closure member 254, if desired for a specific implementation. Whatever the configuration of the cross section of the central hole 240, it will preferably have a generally uniform lateral cross section (as shown in Figure 3B), at least over the intended range of travel of the closure member 254.

[0048] In some embodiments, the valve assembly 230, which may be configured as the closing member 254, may correspond between a first position, generally, of opening openings 248 for fluid flow, and a second position, in general, closing openings 248 for fluid flow. In such configurations, the closure member 254 only needs matching one side of apertures 248 to a position generally in register with apertures 248. This type of configuration lends itself to creating configurations of aperture arrangement and piston displacement and the configuration to optimize the valve for the speed of movement between the open and closed positions, to facilitate a high density of impulses per unit of time. However, other settings are expressly contemplated. As an example, the closing member may move from a first position above the openings 248, to a second position, closing the openings 248, and then to a third position on the opposite side of the openings 248.

[0049] As another alternative, closing member 254 can move not only between essentially a relatively complete "open" position, fully revealing all openings, and a fully "closed" position, completely covering all or a subset of openings 248, but it can also move to one or more intermediate positions, only partially blocking all or a subset of openings 248. In this type of configuration, valve assembly 230 would be capable of generating multiple pulse amplitudes. As another alternative configuration for achieving multiple amplitudes, the openings 248 may be cooperatively arranged with the closing member 254 such that only some openings are closed with the closing member in a first position and all openings are closed with the closing member 254. latch 254 in an axially displaced position. Different cooperating arrangements of openings 248 and the configuration of closing member 254 can be designed to achieve this result. As an example, one or more openings 248 may be arranged to intersect center hole 240, in a first longitudinal position, with one or more other openings 248 arranged to intersect central hole 240 at a next, proximate, but offset, position. longitudinally. Closing member 254 may be configured with a dimension sufficient to lock both sets of openings in the same position and with sufficient displacements to permit only one set of openings to be locked in two additional positions. A possible additional configuration would be for the two sets of openings to define different cumulative flow areas, such that blocking a first set of openings 248 would block a selected percentage of the total fluid flow, while blocking the second set of openings 248 would block a different selected percentage of the total fluid flow, thus activating at least three pulse amplitudes.

[0050] Referring now to Figure 4, the figure illustrates an alternative configuration of a mud pulse generator valve structure, indicated generally at 400. The valve structure 400 is shown in an operating environment within an outer casing. 402. Valve housing 400 includes a valve housing structure, indicated generally at 404, sealed with an outer housing 402. In the example shown, housing structure 404 includes a lower block 406 and an upper block 408. In addition, a conduit section 410 412 provides a path for routing electrical conductors to the upper block 408 and down through the lower block 406 to other devices below the valve structure 400 (only part of the path is visible in the cross section shown). Any block 408 or top section conduit 410 will be configured to provide a plurality of centering beams (e.g. three beams) to maintain the centered orientation of the upper block 408. As with the valve section structure 230 of Figures 2 and 3 , the centering beams will define a plurality of passages, as indicated at 414, in communication with the annular space 416 above the valve structure 400, and extending beyond the upper block 408, and terminating in one or more passages 418 in the lower block 406 extending to respective openings 420 of a surface defining a central hole 422, generally analogous to valve structure 230 discussed above.

[0051] As can be seen from Figure 4, the valve assembly 400 includes a movable, generally annular drive piston, indicated generally at 424, which has a drive section 426 and an integrally formed closure section 428. The drive section 426 is supported in concentric relation to a guide rod 432 by a pair of bearings 430A, 430B. The drive section 426 extends within a drive housing 434 and where the guide rod support 432 maintains a close but spaced relationship between adjacent surfaces of the drive section 426 and housing 436.

[0052] The valve structure 400, like the valve structure 230 of Figures 2 and 3, will be electrically driven, such as using one or more voice coil structures. Thus, the drive section 426 includes a plurality of permanent magnets 438, fixed within one or more cavities 440 in the outside diameter of the drive piston 442. The drive housing 436 supports a plurality of selectively drive coils that extend in concentric relation to drive piston 442. In the example shown, drive housing 436 supports four coils 444A-D. The same options for configuring and controlling coils 444A-D discussed in connection with valve structure 230 of Figure 2C are applicable to this valve structure 400.

[0053] In some examples, coils 444 will be in an oil bath in a sealed chamber 446. The sealed chamber 446 is sealed to a lesser extent by sealed coupling, at 448, between the drive housing 430 and the upper block 408 and to an upper extent on a sealing plate 450. The sealing plate 450 sealingly couples both the guide rod 432 and the drive housing 436. Thus, the coils 444 and any other electrical circuitry that may be included within the chamber 446, are in oil and isolated from well fluid around drive piston 442.

[0054] As can be seen from Figure 4, the closure section 428 does not just define a solid cylindrical sealing surface (as discussed with respect to the central surface 276 of the closure member 254, as shown in Figures 3A-B) . Instead, the closure section 428 defines a plurality of openings 452 each of which will mate with a respective opening 420 in the surface 450 that defines a central hole 422. All longitudinally extending surfaces of the closure section, including the defining apertures 452 and bottom surface 454 are again gradually decreased to reduce restrictions on flow through the fluid.

[0055] In operation, in a manner as described above, activation of the voice coils causes linear forward or backward movement of the drive piston section, causing the closing section 428 to move so that the openings 452 are moved in or out of register with apertures 420, thereby relatively selectively opening or blocking flow between apertures 420 and central orifice 422 to establish pulses in the moving fluid column, as described above.

[0056] Referring now to Figure 5, there is shown an alternative configuration of a mud pulse generator valve structure 500, shown in vertical section. The slurry pulse valve 500 shares many structural and operational features with the valve structure 400 of Figure 4. Therefore, these similarities will not be specifically addressed here. Components that bear a structural and functional similarity to the components in the valve structure 400 will be similarly numbered in Figure 5, without implying that such components are fully identical in all respects to those in Figure 4.

[0057] In some example systems, it may be preferable to have a "fail-safe" mechanism, such that if the slurry pulsation valve fails, it would fail in the "open" position where the slurry flow, through the valve to the drill or other mechanisms below would still occur. This result may be achieved by providing a biasing mechanism arranged to the closure section 428 such that the openings 452 are moved in register with the openings 420 thus resulting in a flow opening to the passages. This biasing mechanism can be one of several types, such as hydraulic, pneumatic (such as an air chamber that serves as a spring), or mechanical. In many exemplary systems, the biasing mechanism will be mechanical, including one or more springs, which may be of various configurations.

[0058] The valve structure 500 again includes an electrically activated drive section, indicated generally at 502, with a generally annular driving piston, indicated generally at 504, which includes a drive section 506 coupled to form a functionally integral unit with lock section 428. A spring frame 506 extends between an upper level lock lower portion 408 and a drive piston upper portion 504. In the example shown, the spring frame 506 includes at least one conduit configured to have two spaced legs 508A, 508B separated by a bridge section 510 such that the spaced legs 508A-B, when pressed together, provide a tendency towards a relatively separate position in which the drive piston 504 is pressed to a position, as illustrated, where openings 452 of closure section 428 are in registration with openings 420, allowing fluid flow between and the same. When the plunger of unit 504 is electrically activated to move to a relatively retracted position, legs that extend generally laterally (with respect to a longitudinal axis extending through valve assembly 500) are compressed against each other. , establishing the polarization.

[0059] In this example, the spring frame 506 is formed of tubes, which allows the spring 506 to also serve as a conduit, which can house electrical conductors to facilitate communication with the mechanisms in the drive piston 504. As noted above , permanent magnet and coil positions can be arranged with any type of component in either stationary or moving components of the drive section. In this example, a plurality of coils 512A-C are supported on movable drive piston 504, while a plurality of permanent magnets 514A-E are supported by stationary center rod 516. In this configuration, coils 512A-C can receive control signals. electrical conductors through conductors that extend through the tubes that form the spring structure 506. The electrical conductors will be in communication with the electronics section as described at 226 in Figure 2C (or relative to member 702 in Figure 7, later shown here ). The spring frame 506 may be formed of any material capable of withstanding downhole conditions and having acceptable fatigue strength provided to withstand the cycle of the valve frame. For a tubular spring mechanism as in the example, titanium is contemplated to be an acceptable material. In place of a single spring structure 506, multiple sources may be used and the springs may be of configurations other than the example described herein. Spring frame 506 and coils 512A-C will again preferably be in an oil bath, generally as described with respect to valve frame 400 of Figure 4.

[0060] As is evident from the above discussion, in the mud pulse generator structure 200 of Figure 2C, all fluid flow is directed around the tapered nose 222 to reach the generator structure 210 and specifically meet the vanes. thereof, before flowing through passages 242A and 242B. Referring now to Figure 6, there is shown an upper portion of an alternative mud pulse generator configuration, indicated generally at 600, which may be used. In this example, components that serve essentially the same functionality as in the mud pulse generator 200 of Figure 2C are similarly numbered. In the mud pulse generator 600, in order to allow fluid control by the generator structure 210, the generator structure is housed within a sleeve structure 602 which fits within the housing structure 202. The sleeve structure 602 defines a central hole 616 and an outer bypass channel 604.

[0061] The generator structure 210 is housed within the central hole 616, which extends longitudinally, beyond the multi-stage adjustable gear 214, to an output port (not shown) in communication with an annular space in communication. with a bypass channel 604. The sleeve structure 602 includes an upper sub 606 that houses a valve structure, indicated generally at 608. The valve structure 608 includes a movable sleeve 610 that is movable longitudinally with respect to the housing structure 202. , and with respect to a bypass port 612. In this example, the valve structure 608 includes a bias spring 614 arranged to bias the movable sleeve 610 to a closed bypass port 612 position. , in the example shown, the valve structure 608 is arranged in such a way that all flow will be directed through the central orifice 616 and therefore to the generator structure 210, in the absence of valve activation. for opening bypass port 612. Valve structure 608 may be actuated by any desired actuation mechanism. For example, an electrical control mechanism as described with respect to valve structure 230 in Figure 2C may be used. Alternatively, other drive mechanisms, including other forms of electrical, hydraulic or mechanical mechanisms, may be used.

[0062] The mud pulse generator 600 is also configured to allow signal communication through the device. Therefore, in this example, the upper sub 606 includes a connector 620 supported on a centering snorkel 622 to facilitate mating with a complementary connector centered within the housing structure 202. In many examples, the connector 620 will be an electrical connector and will be mated to electrical conductors housed within the insulated channel through the sleeve structure 602. In other examples, connector 620 may be an optical connector or a hybrid optical and electrical connector; or it could be a hydraulic connector. In the example shown, the snorkel 622 is described as a separate component of the upper sub 606, and therefore includes a portion of a connector structure 626A that engages a complementary connector structure 626B on the upper sub 606. Thus, in In a configuration in which connector 620 is an electrical connecting member, electrical signals may be transmitted through conductors within channel 628 of snorkel 622 and through connector structure 626A-B to conductors within channel 624 (the conductors are not are specifically represented for clarity).

[0063] As identified earlier in reference to the mud pulse generator structure 200 of Figure 2C, other configurations are possible, including the mud pulse valve structure 230 being arranged on top of the mud pulse generator, with the rest of the identified components being located below the valve structure. Referring now to Figure 7, of which the figure illustrates yet another alternative configuration of a mud pulse generator 700 in which the electronics section (226, as described with reference to Figure 2C) is divided into two parts. In this example, storage mechanisms such as capacitors and/or stacks as previously described will still be located above the valve structure in a first electronics section as depicted in Figure 2C (not shown here). However, other electronic equipment such as control circuits and other systems described earlier in connection with electronics section 226 will be located within a separate electronics section 702 placed below valve structure 230 (partially shown). The electronics section 702 is configured to extend concentrically around a fixed sleeve 704 that defines a center hole portion 240 (of Figure 3A) within a housing assembly 202. Electrical communication is provided through one or more passages, as shown at 706 in the valve structure 700 and through the fixed sleeve 704 (the passages are not visible in the cross section shown). Such passage 706 will preferably extend to reach other passages in the valve structure (as shown at 412 in Figure 4) to reach at least the electronics section 226 above the valve structure; and, in some cases, will extend to an upper connector (as described at 620 in Figure 6), to facilitate connection with other tools located above the mud pulse generator 700. In addition, other passages 710 and/or or connectors 712 may be provided to facilitate communication from the electronics section 702 and/or other structures above it, with tools located below the mud pulse generator 700.

[0064] Referring now to Figure 9, the figure represents a high level flow diagram 800 of an example method of operation of any valve structure 200, valve structure 400 or valve structure 500. As a In the first step, a controller assembly will receive data to be communicated, as indicated in 902. This data receiver may be executed in another mechanism, such as a MWD tool or the LWD in the tool column or by another structure of control, such that data can be collected for transmission by the valve structure.

[0065] Then the data will be prepared for communication. This will typically include encoding the data in accordance with a selected communication protocol, as indicated in 904. Any of a wide variety of communication protocols for communicating data over a series of pulses can be implemented, including the frequency of shift (FSK), phase shift keying (PSK), amplitude shift keying (ASK) and combinations of the above, as well as other communication protocols. An appropriate controller then controls the command structure of the valve structure, as indicated in 906. This functionality can be realized, for example, within an electronics section along the bottom orifice, as described with reference to Figure 8 In the case of the described voice coil drive mechanisms, this will include selectively applying current to one or more of the voice coils to cause linear motion of the closing member, as described above, in accordance with the selected communication protocol, and a selected data rate. As noted above, for some example valve configurations, this may include moving the closing member to positions beyond (respectively) fully "open" and fully "closed", as may be used to provide one or more levels of amplitude. pulse. Furthermore, as mentioned above, this triggering can include sequential actuation of multiple coils.

[0066] Many variations can be made on the structures and techniques described and illustrated here without departing from the scope of the inventive theme. For example, the alternative structures and operations discussed above with respect to each of the valve assemblies 230, the valve assembly 400 and the valve assembly 500 are to be understood as being applicable to other valve assemblies. As just one example, closure member 252 of valve assembly 230 (Figure 3) may be configured to include a generally solid section and a radially apertured section as described with respect to closure section 428 to 452. alternative configurations, as discussed with reference to Figures 6 and 7, may be used in systems with any of the valve sets 230, 400, and/or 500. In addition, many variations can be made from the described example systems, taking into account in view of the disclosure included. Therefore, the scope of the inventive subject is to be determined solely by the scope of the claims that follow and all additional claims supported by the present disclosure, and all equivalents of such claims.

Claims (30)

1. Fluid pulse generator valve, characterized in that it comprises - a housing (154); - a piston chamber (174) within the housing (154), the piston chamber (174) having a downstream portion; - a fluid flow passage (158) inside the housing (154) which extends around a portion of the piston chamber (174) to intersect the downstream portion of the piston chamber (174), wherein the passage fluid flow nozzle (158) extends inwardly at an angle to the downstream portion to intersect the downstream portion of the piston chamber (174); and - a piston (164) (164) arranged inside the piston chamber (174); - a drive mechanism (170) operatively coupled to the piston (164) for controlling movement of the piston (164) over a range of linear motion to selectively obstruct flow at an intersection between the fluid flow passage (158) and the downstream portion of the piston chamber (174), at least a portion of the piston (164) alternating within the downstream portion; and - a radial clearance between the piston (164) and an interior wall of the piston chamber (174), through which some fluid flowing through the fluid passage outside the piston chamber (174) can enter the chamber piston (174), regardless of the position of the piston (164). A fluid pulse generator valve according to claim 1, wherein the fluid flow passage (158) comprises a plurality of fluid flow passages extending around a portion of the flow chamber. piston (174). 3. Fluid pulse generator valve according to claim 2, characterized in that each fluid flow passage (158) intersects the downstream portion at one or more openings (168) on the interior surface of the downstream portion , and wherein the piston (164) selectively obstructs the flow through one or more openings (168). 4. Fluid pulse generator valve according to claim 1, characterized in that the fluid flow passage (158) is sized to pass particles that may be dispersed in a drilling fluid as it flows through the flow passage of fluid (158). 5. Fluid pulse generator valve according to claim 1, characterized in that the linear motion range includes a plurality of different positions, each corresponding to a different degree of flow obstruction, at the intersection between the passage of fluid flow (158) and the downstream portion of the piston chamber (174). 6. Fluid pulse generator valve, according to claim 1, characterized in that the drive mechanism (170) is moved sufficiently to remove particles dispersed in a drilling fluid with the piston (164), when the particles are present at the intersection of the fluid flow passage (158) with the downstream portion of the piston chamber (174). 7. Fluid pulse generator valve according to claim 1, characterized in that the piston (164) is sealed with an interior wall of the piston chamber (174). 8. Fluid pulse generator valve, according to claim 7, characterized in that it further comprises a dynamic seal isolating at least a portion of the actuation mechanism (170) from a fluid flowing in the portion a downstream of the piston chamber (174). 9. Fluid pulse generator valve, characterized in that it comprises: a housing (154); - a piston chamber (174) within the housing (154), the piston chamber (174) having a portion defined by a surface, a piston closing member (164) alternating within the portion; - a fluid flow passage (158) within the housing (154) that extends to intersect the piston chamber (174) at one or more openings (168) in the surface; and - the closing member disposed within the piston chamber (174) and linearly movable within the piston chamber (174) to selectively obstruct flow through one or more openings (168) in the surface of the piston chamber (174). ), wherein the enclosing member obstructs flow through one or more openings (168), and wherein a radial clearance is maintained between the enclosing member and the surface of the piston chamber (174), through which some fluid flowing through the fluid passage outside the piston chamber (174) can enter the piston chamber (174), regardless of a position of the closing member (254). 10. Fluid pulse generator valve according to claim 9, characterized in that it further comprises an actuation mechanism (170) comprising an electrical mechanism for moving the closing member through a range of linear motion including a plurality of different positions, each corresponding to a different degree of flow obstruction at the intersection between the fluid flow passage (158) and the downstream portion of the piston chamber (174). 11. Fluid pulse generator valve according to claim 9, characterized in that it further comprises an actuation mechanism (170) operatively coupled to the piston (164) to control the movement of the piston (164) along a range of linear motion including a plurality of different positions, each corresponding to a different degree of flow obstruction at the intersection between the fluid flow passage (158) and the downstream portion of the piston chamber (174), wherein the drive mechanism (170) comprises an electromagnetic mechanism. 12. Fluid pulse generator valve according to claim 9, characterized in that the valve comprises a plurality of fluid flow passages that intersect the piston chamber portion (174). 13. Fluid pulse generator valve, according to claim 9, characterized in that the surface is defined by a uniform hole in which the piston closing member (164) reciprocates. 14. Fluid pulse generator, characterized in that it comprises: - a housing assembly (202) that defines at least one flow passage; and - a valve assembly (230) within the housing assembly (202), the valve assembly (230) including an actuation member (252) operatively coupled to an actuation mechanism (280) and movable along a range of motion along a linear axis, the drive member (252) including a closure section for opening or closing a fluid passage opening (248) in an inner surface of the valve assembly (230) which is radially disposed with respect to the closure section alternating along the linear axis, and the closure section comprising a generally cylindrical outer surface supported relative to a central hub (274) by a plurality of spokes (272). 15. Fluid pulse generator, according to claim 14, characterized in that a portion of the closing section extends along the linear axis after the fluid passage opening (248) when the valve assembly (230) obstructs flow through fluid passage opening (248). 16. Fluid pulse generator, characterized in that it comprises: - a valve assembly (230) defining a flow passage, the flow passage extending to a plurality of openings (248) in a surface defining a uniform bore (240) for an established distance with the plurality of openings (248) disposed around a perimeter of the surface; - a valve piston (250) having a closing member (254) linearly movable within the uniform bore (240), the closing member (254) movable between a first position, allowing fluid flow between the plurality of openings (248) and the uniform hole (240), and a second position, obstructing the flow of fluid between at least some of the openings (248) and the uniform hole (240) and wherein the closing member (254) comprises a generally cylindrical outer surface supported relative to a central hub (274) by a plurality of spokes (272); - an actuation mechanism (280) operatively coupled to the piston (250) of the valve; and - a controller operatively coupled to the drive mechanism (280) for moving the closing member (254) between the first and second positions. 17. Fluid pulse generator, according to claim 16, characterized in that the drive mechanism (280) is an electrical mechanism. 18. Fluid pulse generator, according to claim 16, characterized in that the closing member (254) is still movable to at least a third position. 19. Fluid pulse generator, according to claim 16, characterized in that the drive mechanism (280) is an electromagnetic mechanism. 20. Fluid pulse generator, according to claim 19, characterized in that the electromagnetic drive mechanism (280) includes at least one permanent magnet on a first component and at least one coil (258A) on a second component. 21. Fluid pulse generator, according to claim 16, characterized in that the controller will trigger the drive mechanism (280) according to at least one protocol selected from the group of: FSK, PSK, ASK and combinations of the above. 22. Fluid pulse generator, according to claim 16, characterized in that the generally uniform hole (240) has a circular cross-section for the established distance. 23. Fluid pulse generator, characterized in that it comprises: - a housing (202); - a piston chamber within the housing (202), the piston chamber having a portion defined by a surface; - a fluid flow passage within the housing (202) that extends to intersect the piston chamber at one or more openings (248) in the surface; and - a piston (250) disposed within the piston chamber and linearly movable within the piston chamber along a linear axis to selectively obstruct flow and allow flow through one or more openings (248) in the surface of the chamber of piston; - wherein the piston (250) comprises the closing member (254) having a generally cylindrical outer surface supported relative to a central hub (274) by a plurality of spokes (272); - a drive mechanism (280) operably coupled to move the piston (250) between positions to obstruct or allow flow through the one or more openings (248); - a power source (210); and - a controller coupled to the power source (210) and the drive mechanism (280) to control the drive mechanism (280) to move the piston (250) to generate a series of fluid pulses. 24. Fluid pulse generator according to claim 23, characterized in that it further comprises a plurality of fluid flow passages within the housing (202) and which extend to intersect the piston chamber at one or more openings (248). 25. A fluid pulse generator as claimed in claim 23, wherein the fluid flow passage extends around a portion of the piston chamber (250) to radially intersect the piston chamber portion (250) ). 26. Fluid pulse generator, according to claim 23, characterized in that a portion of the drive mechanism (280) is arranged radially with respect to a portion of the piston (250). 27. Fluid pulse generator, according to claim 24, characterized in that a portion of the drive mechanism (280) extends concentrically to a portion of the piston (250). 28. Method of generating fluid pulses in a fluid column, characterized in that it comprises: - driving a fluid pulse generator (200) arranged in a tool column within an exploration well (116), the column of tools containing the fluid column, the fluid pulse generator (200) comprising, - a housing assembly (202) defining a plurality of openings (248) disposed in a surface defining a generally uniform hole (240) for an established distance; - a valve assembly (230) having a closing member (254) linearly movable within the generally uniform bore (240), the closing member (254) supporting a sealing surface, the closing member (254) ) is movable between a first position in which the sealing surface allows relatively free fluid flow between the plurality of openings (248) and the generally uniform bore (240), and a second position in which the sealing surface relatively restricts flow. of fluid between the plurality of openings (248) and the bore; and - a drive mechanism (280) operatively coupled to the closing member (254) for moving the closing member (254) between the first and second positions; and wherein the drive of the fluid pulse generator (200) comprises, - receiving information to be transmitted through the fluid column, - encoding the information in accordance with a selected communication protocol, and, - controlling the drive mechanism (280). ) to move the closure member (254) in accordance with the encoded information to generate a corresponding series of fluid pulses in the fluid column. 29. Method according to claim 28, characterized in that the closing member (254) is still movable to a third position, and the drive mechanism (280) being still operable to move the closing member (254) for the third position, as well as for the first and second positions. 30. Method according to claim 29, characterized in that the control of the actuation mechanism (280) further comprises: - receiving feedback inputs from sensors outside the valve mechanism, and - adjusting the actuation mechanism (280) in response to such returns.

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